1. Technical Field
Example embodiments relate generally to semiconductor devices. For example, example embodiments of the inventive concepts relate to a resistor array formed using a semiconductor substrate and a semiconductor device including the same.
2. Description of the Related Art
Resistors used in semiconductor devices may be classified into active resistors and passive resistors. The active resistors include a resistive portion formed in a semiconductor substrate. The passive resistors correspond to separate resistive structures formed on the semiconductor substrate.
The active resistors may include diffusion regions for resistive materials. Impurities with an opposite conductive type to the semiconductor substrate may be implanted into the substrate to form the diffusion regions. Generally, the passive resistors are formed on the semiconductor substrate and surrounded by insulating materials. Therefore, compared with the active resistor, the passive resistor may have less leakage current and less deviation of resistance distribution resulting from variations in the manufacturing process.
In forming an integrated circuit using a semiconductor substrate, global planarization techniques are used to achieve flatness corresponding to a depth of focus (DOF) under the circumstance of an ever-decreasing design rule.
A chemical-mechanical polishing (CMP) process, which is one conventional planarization method, is widely used to realize desired flatness. The CMP processes are classified into oxide CMP, metal CMP and polysilicon CMP according to the polishing material used. In a manufacturing process of a passive resistor, the CMP process is performed several times, and the dishing effect may occur during the CMP process. A dishing effect means that some portion of the polished plane is lowered according to the material distribution on the polishing layer.
This dishing effect may cause instability of connection between the passive resistor and metal wiring. In addition, the resistance of the passive resistor may be unpredictably varied due to the dishing effect.